From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.5 required=3.0 tests=BAYES_00,HK_RANDOM_FROM, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8BE03C433DF for ; Fri, 17 Jul 2020 01:23:08 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5EE54207BC for ; Fri, 17 Jul 2020 01:23:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5EE54207BC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bu.edu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47170 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jwF5f-0001zm-GC for qemu-devel@archiver.kernel.org; Thu, 16 Jul 2020 21:23:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53688) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jwF55-0001XW-A0 for qemu-devel@nongnu.org; Thu, 16 Jul 2020 21:22:31 -0400 Received: from relay64.bu.edu ([128.197.228.104]:57168) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jwF52-0007Gc-S0 for qemu-devel@nongnu.org; Thu, 16 Jul 2020 21:22:30 -0400 X-Envelope-From: alxndr@bu.edu X-BU-AUTH: mozz.bu.edu [128.197.127.33] Received: from BU-AUTH (localhost.localdomain [127.0.0.1]) (authenticated bits=0) by relay64.bu.edu (8.14.3/8.14.3) with ESMTP id 06H1LpoW022538 (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Thu, 16 Jul 2020 21:21:56 -0400 Date: Thu, 16 Jul 2020 21:21:51 -0400 From: Alexander Bulekov To: Li Qiang Subject: Re: [PATCH] net: check payload length limit for all frames Message-ID: <20200717012151.tlfmc6hsfia22f4e@mozz.bu.edu> References: <20200716192335.1212638-1-ppandit@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: NeoMutt/20180716 Received-SPF: pass client-ip=128.197.228.104; envelope-from=alxndr@bu.edu; helo=relay64.bu.edu X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/16 21:22:27 X-ACL-Warn: Detected OS = Linux 2.6.x X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, HK_RANDOM_ENVFROM=0.001, HK_RANDOM_FROM=1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Prasad J Pandit , Jason Wang , Dmitry Fleytman , QEMU Developers , P J P Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 200717 0853, Li Qiang wrote: > P J P 于2020年7月17日周五 上午3:26写道： > > > > From: Prasad J Pandit > > > > While sending packets, the check that packet 'payload_len' > > is within 64kB limit, seems to happen only for GSO frames. > > It may lead to use-after-free or out-of-bounds access like > > issues when sending non-GSO frames. Check the 'payload_len' > > limit for all packets, irrespective of the gso type. > > > > Hello Prasad, > Which issue are you trying to solve, any reference linking? > > I also send a patch related this part and also a UAF. > > Thanks, > Li Qiang Hi Li, Prasad, I reported a UAF privately to QEMU-Security in May. I believe the one Li is referring to is this one https://bugs.launchpad.net/qemu/+bug/1886362 When I saw Prasad's email, I was worried that I reported the same bug twice, but I can still reproduce LP#1886362 with Prasad's patch. On the other hand, I cannot reproduce either issue with Li's patch: Message-Id: <20200716161453.61295-1-liq3ea@163.com> Based on this, I think there were two distinct issues. Both of the crashes rely on e1000e tx loopback into e1000e MMIO. Since Li's patch adds a TX bh, it seems to mitigate such types of issues. Sorry about any confusion. -Alex > > Reported-by: Alexander Bulekov > > Signed-off-by: Prasad J Pandit > > --- > > hw/net/net_tx_pkt.c | 10 ++++------ > > 1 file changed, 4 insertions(+), 6 deletions(-) > > > > diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c > > index 162f802dd7..e66998a8f9 100644 > > --- a/hw/net/net_tx_pkt.c > > +++ b/hw/net/net_tx_pkt.c > > @@ -607,12 +607,10 @@ bool net_tx_pkt_send(struct NetTxPkt *pkt, NetClientState *nc) > > * Since underlying infrastructure does not support IP datagrams longer > > * than 64K we should drop such packets and don't even try to send > > */ > > - if (VIRTIO_NET_HDR_GSO_NONE != pkt->virt_hdr.gso_type) { > > - if (pkt->payload_len > > > - ETH_MAX_IP_DGRAM_LEN - > > - pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len) { > > - return false; > > - } > > + if (pkt->payload_len > > > + ETH_MAX_IP_DGRAM_LEN - > > + pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_len) { > > + return false; > > } > > > > if (pkt->has_virt_hdr || > > -- > > 2.26.2 > > > >